scholarly journals Second-order Direct Analysis of Steel Structures made of tapered members

2018 ◽  
Author(s):  
Siu-lai Chan ◽  
SW Liu ◽  
YP Liu
Keyword(s):  
Steel Structures ◽  
Direct Analysis ◽  
Rolling Process ◽  
Second Order ◽  
Steel Plates ◽  
Effective Length ◽  
Robotic Welding ◽  
Weight Saving ◽  
Tapered Members ◽  
Hot Rolled

Mild steel hot-rolled sections are commonly prismatic because of the rolling process with a furnace, but welded sections made from steel plates do not have such a constraint, especially when robotic welding machines are used. The weight saving could be very significant by, say, using wide flanged section at mid-span and a small flanged section at ends of a simply supported beam. However, design codes do not provide formulae for buckling check of tapered members. This paper proposes a code-free second-order direct analysis for stabilty design of steel frames made of tapered members. The design is further applied to a single layered mega space frame of 136m span. In the whole design process based on the concept of Second-order Direct Analysis, no uncertain effective length and independent member buckling checking are required. 

scholarly journals CONSIDERATIONS ON THE DIFFUSE SEISMICITY ASSUMPTION

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Jorge Daniel Riera ◽  
Ignacio Iturrioz
Keyword(s):  
Steel Structures ◽  
Direct Analysis ◽  
Second Order ◽  
Effective Length ◽  
Order Effects ◽  
Analysis Method ◽  
Order Analysis ◽  
3D Space ◽  
Effective Length Method ◽  
Diffuse Seismicity

Second-order effects were historically included by the effective length method (K concept). All the studies about that methodology have been developed in frame plane, with regular rectangular frames. The new way to include those effects is the use of second-order analysis, direct analysis method or alternative simplified options. This methodology was included in ANSI AISC360 in the 2005 version and in the 2010 version. As before, the studies already developed for DAM analysis are in plane. In this paper, the K concept is revisited by numerical analysis, and extended to the 3D space. Using models of symmetric and non-symmetric industrial steel structures in plane, 3D stability analyses were developed, and the results were compared with plane behavior. Several conclusions and recommendations were exposed, resulting from the analyzed models. Keywords: Second-order analyses, steel structures, irregular 3D frames.

scholarly journals Evaluation of notional loads magnitude to three calibration concentric braced frames subjected to seismic loads in Indonesia

2019 ◽  
Vol 276 ◽  
pp. 01005
Author(s):  
Heru Purnomo ◽  
Mulia Orientilize ◽  
Sjahril A Rahim ◽  
Firdaus A Zaki
Keyword(s):  
Numerical Study ◽  
Direct Analysis ◽  
Second Order ◽  
Effective Length ◽  
Seismic Load ◽  
Seismic Loads ◽  
Elastic Analysis ◽  
Braced Frames ◽  
Braced Frame ◽  
Geometric Imperfection

The changing of SNI 03-1729 from 2002 to 2015 which refer to AISC 2010 change the method of steel stability analysis from effective length method (ELM) to direct analysis method (DAM). DAM use second order elastic analysis, accommodate strength reduction, geometric imperfection presented as notional load, and take buckling factor (K) equal to 1. Numerical study has been conducted to find out the appropriate magnitude of notional loads on concentric braced frame subjected to seismic load in Indonesia. Experimental results from three different calibration frames from previous research were used as reference. The frames consisted of 1-story, 3-stories, and 5-stories were reanalyzed by using SAP software with four different methods: ELM first order elastic analysis, ELM second order elastic analysis, and DAM with different notional loads coefficient as 0.002 and 0.003. Seismic loads according SNI 1726:2012 in three seismic regions were considered.

Second-Order Direct Analysis of Domelike Structures Consisting of Tapered Members with I-Sections

2016 ◽  
Vol 142 (5) ◽  
pp. 04016009 ◽  
Author(s):  
Si-Wei Liu ◽  
Rui Bai ◽  
Siu-Lai Chan ◽  
Yao-Peng Liu
Keyword(s):  
Direct Analysis ◽  
Second Order ◽  
Tapered Members

New Canadian provisions for the design of steel beam–columns

1990 ◽  
Vol 17 (6) ◽  
pp. 873-893 ◽  
Author(s):  
D. J. L. Kennedy ◽  
A. Picard ◽  
D. Beaulieu
Keyword(s):  
Traditional Method ◽  
Geometric Analysis ◽  
Steel Structures ◽  
Second Order ◽  
Effective Length ◽  
Order Effects ◽  
Limit States ◽  
Cross Sectional ◽  
Out Of Plane ◽  
Areas Of Concern

The beam–column interaction equations of the Canadian Standards Association Standard CAN3-S16.1-M84 "Steel structures for buildings — limit states design" are reviewed and areas of concern in the formulations are addressed. The interaction equations developed for the 1989 edition of the standard, CAN3-S16.1-M89 "Limit states design of steel structures," and the methods of dealing with the areas of concern in the previous standard are presented. The new standard requires that at least an approximate second-order geometric analysis be carried out. For frames dependent on the frame stiffness for lateral stability, no longer is the traditional method, using effective length factors greater than one, allowed. Unlike the current American Institute of Steel Construction "Load and resistance factor design'' (AISC LRFD) specification, two sets of interaction equations, one for in-plane member strength and the other for out-of-plane stability, are used. This results in considerably less unnecessary conservatism. In both sets of interaction equations, the component of the moment due to translation is increased by the second-order effects. The "double ω" problem has been resolved and the minimum sway effects for the gravity loading case have been increased substantially to guard against sidesway buckling. A design example using the new standard is given. By means of a series of analytical examples, the requirements of S16.1-M89 are compared with the traditional method of S16.1-M84. For frames with direct-acting bracing, S16.1-M89 gives interaction values about 1.15 times those of the previous standard with a coefficient of variation of 0.08, while for unbraced frames the corresponding values are 0.98 and 0.07. The S16.1-M89 values reflecting greater rigor in a number of areas are considered the more valid. The S16.1-M89 standard would give comparable results to the AISC LRFD specification for class 1 sections when out-of-plane behaviour governs. The latter specification does not specifically cover cross-sectional strength and in-plane behaviour as does S16.1-M89. Key words: beam–column, stability, strength, bending, compression, standards.

The Practical Calculation Charts to Determine Column Effective Length of Framework and Bent Framework

2013 ◽  
Vol 351-352 ◽  
pp. 1052-1056
Author(s):  
Zhi Sheng ◽  
Dong Hua Zhou
Keyword(s):  
Axial Force ◽  
Steel Structures ◽  
Order Theory ◽  
Second Order ◽  
Effective Length ◽  
Practical Calculation ◽  
Column Length ◽  
Displacement Method ◽  
Special Cases ◽  
Stability Checking

Calculation of effective length of columns is key of stability checking in design, therefore some formulas and tables are given in Code for Design of Steel Structures (GB 50017-2010), which show some application Limitations. These formulas and tables are made based on assumptions for regular frames. For some special cases, such as existence of the large difference of the column axial force or column length among the framework columns, these formulas and tables are no longer applicable. The practical calculation charts are derived by authors by using the displacement method with the second-order theory, which can be used to quickly determine column effective length and show intuitive trends of the lengths.

scholarly journals Root Cause Analysis of Surface Cracks in Heavy Steel Plates during the Hot Rolling Process

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 801 ◽  
Author(s):  
Abbas Bahrami ◽  
Mahdi Kiani Khouzani ◽  
Seyed Amirmohammad Mokhtari ◽  
Shahin Zareh ◽  
Maryam Yazdan Mehr
Keyword(s):  
Rolling Process ◽  
Processing Parameters ◽  
Constructional Steel ◽  
Steel Plates ◽  
Surface Cracks ◽  
Heavy Plate ◽  
Root Cause ◽  
Hot Rolling Process ◽  
Electron Microscopes ◽  
Hot Rolled

This paper investigates the root cause of the formation of surface cracks on hot-rolled C–Mn constructional steel heavy plates. Cracks are rather evenly distributed over the surface in the form of colonies of cracks. Samples were cut from the heavy plate. The microstructure of samples in the as-cast and hot-rolled states were studied using optical and electron microscopes as well as energy dispersive X-ray spectroscopy (EDS). Results show that cracks are heavily oxidized. De-carburized areas are also seen alongside cracks. The crack tip is in the form of a deer-horn, indicating that crack branching has taken place during deformation. The crack initiation sites are V-shaped grooves on the surface of as-cast slabs. Correlations between microstructures, processing parameters, and crack formation are discussed.

scholarly journals Direct plastic analysis of steel structures by flexibility-based element with initial imperfection

2018 ◽  
Author(s):  
Siu Lai Chan ◽  
Yaopeng Liu ◽  
G. P. Shu
Keyword(s):  
Plastic Hinge ◽  
High Stress ◽  
Three Dimensional ◽  
Initial Imperfection ◽  
Steel Structures ◽  
Direct Analysis ◽  
Second Order ◽  
Analysis And Design ◽  
Fiber Plastic ◽  
Plastic Analysis

Second-order direct analysis has been used in some regions for reliable analysis and design of steel structures. Currently, the stiffness-based element is widely used with accuracy improved by enforcing equilibrium along mid-span or “stations” along the member length in order to achieve equilibrium which is not guaranteed along an element. In this paper, a flexibility-based beam-column element considering member imperfection based on Hellinger-Reissner functional is developed and used for practical second-order direct analysis. This new element is a flexibility-based element with member initial bowing at the element level for direct analysis of three-dimensional frame analysis whereas previous flexibility-based elements assumed perfectly straight geometry for the element. The fiber plastic hinge approach is adopted to account for the distributed plasticity of a section. The new flexibility-based element performs excellently for modeling of members under high stress with material yielded as the conventional stiffness-based element has less accuracy when few elements are used in modeling a plastic member. This will significantly enhance accuracy and computational efficiency for direct plastic analysis which can then be more widely used in practical design. Several examples are employed to validate the accuracy and efficiency of the proposed element along this line of thought.

YOUNGSTOWN YS-T50 to YS-T140 STEELS

Alloy Digest ◽  
1977 ◽  
Vol 26 (4) ◽  
Keyword(s):  
Physical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Heat Treating ◽  
Steel Alloy ◽  
Bend Strength ◽  
Weight Saving ◽  
Cold Rolled ◽  
Hot Rolled ◽  
Minimum Yield

Abstract YS-T 50 to YS-T 140 Steels comprise a series of high-strength, cold-rolled steels designed to meet performance and weight-saving objectives. They are an extension of Youngstown's series of hot-rolled high-strength steels (see Youngstown YS-T Steel, Alloy Digest SA-261, March 1971). The YS-T 50 to YS-T 140 steels have minimum yield strengths ranging from 50,000 psi to 140,000 psi. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength. It also includes information on heat treating, machining, and joining. Filing Code: SA-331. Producer or source: Youngstown Sheet and Tube Company.

DOMEX 550MC

Alloy Digest ◽  
2009 ◽  
Vol 58 (3) ◽  
Keyword(s):  
Physical Properties ◽  
Hsla Steel ◽  
Steel Structures ◽  
High Strength ◽  
Heat Treating ◽  
Bend Strength ◽  
Cold Forming ◽  
Wide Range ◽  
Hot Rolled ◽  
Earthmoving Machines

Abstract Domex 550MC is a hot-rolled, high-strength low-alloy (HSLA) steel for cold forming operations. It is available in thicknesses of 2.00-12.80 mm. The alloy meets or exceeds the requirements of S550MC in EN 10149-2. Applications include a wide range of fabricated components and steel structures, including truck chassis, crane booms, and earthmoving machines. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fatigue. It also includes information on forming, heat treating, and joining. Filing Code: SA-594. Producer or source: SSAB Swedish Steel Inc.

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